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Finding the Fourth Proportional to 855.47, 1,172.85 and 839.90

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Solution

The fourth proportional to 855.47, 1,172.85 and 839.90 is: 1,151.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.47 : 1,172.85 = 839.90 : x
  2. Step 2: Convert to fraction form
    855.47/1,172.85 = 839.90/x
  3. Step 3: Cross multiply
    855.47x = 1,172.85 × 839.90
  4. Step 4: Simplify right side
    855.47x = 985,066.65
  5. Step 5: Solve for x
    x = 985,066.65/855.47
  6. Step 6: Final answer
    x = 1,151.50

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.